A Beautiful, Bewitching Map of Portland's Aging Buildings

With this kaleidoscopic map, Justin Palmer takes a digital chainsaw to Portland and shows the world its rings. Track the color changes to see where old neighborhoods meld with new ones: Structures shown in aquamarine date from the 1890s, purple from the 1950s and hot pink to white from 1970 onward.

There are more than half a million building records in Portland's archives that have dates attached to them. Perhaps because he was deprived of such reams of information growing up in a picayune Mississippi town, Palmer felt compelled to map them in dazzling peacock hues. "I thought it could be cool to see what the data would look like on a map using a style similar to what Eric Fischer used for MapBox and Open StreetMap," says Palmer, a 33-year-old Pearl District resident who works at GitHub.

In "The Age of a City," blooms of magenta show off the relative youth of satellite communities like Beaverton, Happy Valley and outer Gresham, and a solid wash of chilly blue reveals central Portland's geezer status. When making the map, Palmer was pleasantly surprised by a few patterns, such as the way older and more developed neighborhoods tended to follow historical streetcar lines. Then there's Interstate 205 acting like a wall separating two oceans of different-era structures, which the map's creator is still scratching his head about.

"Many of the structures west of 205, even outside of the city center, trend in the early 1900s, and then you have the interstate and everything east of it trending in the 1950s and '60s," he says. "According to Wikipedia, I-205 didn't exist until 1975, so I'm not sure why this divide exists."

• The dream of the '90s is still alive in 75,434 structures. The 1890s haven’t fared so well, with only 942 structures still standing.

• The busiest year was 1978 with 10,265 structures listed.

• It looks like '50s-era housing development relied more on the grid system, than say, the '80s and '90s where the cul-de-sac was seen more often.

If you look hard enough, you can also see what appears to be the signature of the subprime mortgage crisis. "The correlation with the housing crisis was particularly interesting," Palmer says. "I don't think we really knew what was happening until the recession hit in 2008, but you can see a sharp decline in new structures starting in 2006."

Here's a far-out view:

Newer development around the University of Portland and the Swan Island Basin:

Ordered streets in the Irvington 'hood:

The meandering roads of Beaverton:

Ladd's Addition, a "vortex" of standalone homes and the oldest planned residential development in the city:

Several miles to the south is Oregon City, the first urban area west of the Rockies to undergo incorporation. It's home to some of the Portland area's oldest buildings, like the Francis Ermatinger House from 1845 and the 1849 residence of Dr. Forbes Barclay, “[a]rctic explorer, physician, public official, philanthropist” and mayor of the town: